Method for manufacturing golf club head

ABSTRACT

A method for manufacturing a golf club head includes producing a main body wax pattern and an accessory wax pattern. An engaging portion of the main body wax pattern is engaged with an engaging portion of the accessory wax pattern, with a gap being defined between the first engaging portion and the second engaging portion. Then, a low-viscosity volatile solvent is filled into the gap for forming a club head wax pattern by means of bonding of dissolved wax materials of the main body wax pattern and the accessory wax pattern. The club head wax pattern is impregnated in slurry to form a ceramic shell, which is then heated the ceramic shell to release wax in the ceramic shell. Finally, a casting procedure is carried out to form a club head casting in the ceramic shell.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing a golf club head. In particular, the present invention relates to a method for manufacturing a golf club head by means of a main body wax pattern and an accessory wax pattern.

2. Description of Related Art

Generally, a conventional method well-known in the art is used to manufacture an iron club head and shall be described below. Molten wax is filled into two separate molds (not shown) for forming a first wax pattern (a main body wax pattern) 10 and a second wax pattern (a striking plate wax pattern) 20. The wax patterns 10 and 20 are bonded together, as shown in FIG. 1 of the drawings. The wax patterns 10 and 20 are impregnated in slurry to form a ceramic shell 30, which is then heated to melt the wax patterns 10 and 20. The molten wax is released from the ceramic shell 30, as shown in FIG. 2. The ceramic shell 30 includes a protrusion (not labeled) corresponding to the shape of a back cavity of a golf club head to be manufactured. The ceramic shell 30 further includes a filler or port (not shown) in a side thereof. Molten metal is poured into the ceramic shell 30 via the port, forming a golf club head in the ceramic shell 30 after cooling and hardening of the molten metal. The golf club head 40 (FIG. 3) is accessed by means of breaking the ceramic shell 30.

An integrally formed golf club head can be obtained by the above-mentioned method, with a back cavity 41 directly formed in a rear side of the golf club head 40, which is particularly useful to produce a back cavity 41 with an undercut for improving the striking effect of the golf club head 41 or for providing a desired shape for the golf club head 40.

Molten wax is filled into a jointing area between the main body wax pattern 10 and the striking plate wax pattern 20 when bonding the two wax patterns 10 and 20 together. Nevertheless, when the filling is not effectively carried out, a gap “a” (see FIG. 1 a) exists between the two wax patterns 10 and 20, leading to permeation of the slurry into the gap “a” during the impregnating procedure. As a result, a burr “b” (see FIG. 2 a) is formed inside the ceramic shell 30 after release of the wax patterns 10 and 20, and the burr “b” results in generation of a gap “c” (see FIG. 3 a) in the resultant golf club head 40, which may cause disqualification of the golf club head 40. Further, as illustrated in FIG. 2 b, a filling a' (such as molten wax, resin, silicon rubber, or hot-dissolving glue) may be filled into the gap “a” while manufacturing the wax patterns. However, the filling a' generally has a relatively high viscosity (e.g., the wax at 100° C. has a viscosity higher than 100 cps) such that the filling a' is difficult to enter the gap “a” by capillary action. Instead, the filling a' tends to cool and harden and thus remains on the surface of the gap “a” when comes in contact with the wax patterns 10 and 20. Irregular protrusions are formed on the joint area between the wax patterns 10 and 20 though the gap “a” can be reliably filled with the filling a'. The casting of the golf club head 40 requires troublesome surface finishing, which would be extremely difficult if the irregular protrusions are formed on a joint area in the back cavity 41 of the golf club head 40, as it is difficult to use a grinding tool in the back cavity 41. The surface finishing cost is increased and the manufacturing time is prolonged.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a method for manufacturing a golf club head with reliable gap filling effect.

Another object of the present invention is to provide a method for manufacturing a golf club head with a flush bonding surface.

A further object of the present invention is to provide a method for manufacturing a golf club head with lowered precision requirements for the wax patterns.

Still another object of the present invention is to provide method for manufacturing a golf club head with improved bonding quality between the wax patterns.

Yet another object of the present invention is to provide a method for manufacturing a golf club head with improved casting surface evenness.

Still another object of the present invention is to provide method for manufacturing a golf club head with reduced surface grinding work for the golf club head casting.

Yet another object of the present invention is to provide method for manufacturing a golf club head with increased qualified product ratio.

SUMMARY OF THE INVENTION

In accordance with an aspect of the invention, a method for manufacturing a golf club head comprises:

-   -   producing a main body wax pattern having a first engaging         portion and an accessory wax pattern having a second engaging         portion;     -   engaging the first engaging portion of the main body wax pattern         with the second engaging portion of the accessory wax pattern,         with a gap being defined between the first engaging portion and         the second engaging portion;     -   filling a low-viscosity volatile solvent into the gap for         forming a club head wax pattern by means of bonding of dissolved         wax materials of the main body wax pattern and the accessory wax         pattern; and     -   impregnating the club head wax pattern in slurry to form a         ceramic shell and then heating the ceramic shell to release wax         in the ceramic shell; and     -   proceeding with a casting procedure to form a club head casting         in the ceramic shell.

The low-viscosity volatile solvent is a volatile organic solvent having a viscosity smaller than 5 cps. The low-viscosity volatile solvent is selected from the group comprising aryl solvent, aliphatic solvent, and cyclane solvent. Preferably, the low-viscosity volatile solvent is selected from the group comprising toluene, xylene, acetone, petroleum leve, pentane, hexane, propyl bromide, and banana oil and combinations thereof.

In an embodiment of the invention, the accessory wax pattern is a striking plate wax pattern. The main body wax pattern includes a back cavity extending from a front side of the main body wax pattern through a rear side of the main body wax pattern. The back cavity has an undercut. The back cavity includes a front side that forms the first engaging portion, and the striking plate wax pattern includes a rear side having a perimeter edge that forms the second engaging portion.

In another embodiment of the invention, the accessory wax pattern is a wax pattern for sealing. A bottom wall delimiting the back cavity includes a through-hole. A portion of a perimeter wall delimiting the through-hole forms the first engaging portion. The wax pattern for sealing includes a perimeter that forms the second engaging portion. In a case that the wax pattern for sealing seals a lower end of the through-hole, the club head casting manufactured from the ceramic shell includes a compartment with an upwardly facing opening. In another case that the wax pattern for sealing seals an upper end of the through-hole, the club head casting manufactured from the ceramic shell includes a compartment with a downwardly facing opening.

Other objects, advantages and novel features of this invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a conventional club head wax pattern for manufacturing a golf club head;

FIG. 1 a is enlarged view of a circled portion in FIG. 1;

FIG. 1 b is a view similar to FIG. 1 a, wherein a filling is filled into a gap;

FIG. 2 is a sectional view of a ceramic shell obtained from the club head wax pattern in FIG. 1;

FIG. 2 a is an enlarged view of a circled portion in FIG. 2;

FIG. 3 is a sectional view of a golf club head obtained from the ceramic shell in FIG. 2;

FIG. 3 a is an enlarged view of a circled portion in FIG. 3;

FIG. 4 is a schematic flow chart illustrating a method for manufacturing a golf club head in accordance with the present invention;

FIG. 5 is an exploded perspective view of a club head wax pattern obtained from a first step of the method in accordance with the present invention;

FIG. 6 is a sectional view of the club head wax pattern after a second step of the method in accordance with the present invention;

FIG. 6 a is an enlarged view of a circled portion in FIG. 6;

FIG. 7 is a view similar to FIG. 6 a, showing a third step of the method in accordance with the present invention;

FIG. 8 is a view similar to FIG. 7, showing the resultant structure after the third step;

FIG. 9 is a sectional view showing a ceramic shell obtained during a fourth step of the method in accordance with the present invention;

FIG. 10 is a sectional view showing a ceramic shell obtained after release of wax;

FIG. 11 is a sectional view showing a golf club head manufactured from the ceramic shell in FIG. 10;

FIG. 12 is an exploded perspective view of a modified embodiment of a club head wax pattern obtained from a first step of the method in accordance with the present invention; and

FIG. 13 is a perspective view of a golf club head manufactured from the club head wax pattern in FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are now to be described hereinafter in detail, in which the same reference numerals are used in the preferred embodiments for the same parts as those in the prior art to avoid redundant description.

Referring to FIGS. 4 and 5, a first step of a method for manufacturing a golf club head in accordance with the present invention comprises producing a main body wax pattern 10 and an accessory wax pattern such as a striking plate wax pattern 20. The main body wax pattern 10 includes a first engaging portion 12 and the accessory wax pattern includes a second engaging portion 21.

More specifically, molten wax is filled into two molds (not shown) respectively for the main body wax pattern 10 and the accessory wax pattern. The main body wax pattern 10 forms the primary part of a club head wax pattern for manufacturing a golf club head, with a back cavity 11 extending from a front side through a rear side of the main body wax pattern 10 and with a stepped portion being defined' in a front side of the back cavity 11 and forming the first engaging portion 12. The accessory wax pattern is, e.g., a striking plate wax pattern 20, with a perimeter edge of the rear side of the striking plate wax pattern 20 forming the second engaging portion 21. The stepped portion forming the first engaging portion 12 has a maximum width slightly greater than that of the striking plate wax pattern 20.

Referring to FIGS. 4, 6, and 6 a, the second step of the method for manufacturing a golf club head in accordance with the present invention comprises bonding (e.g., by adhering) the first engaging portion 12 of the main body wax pattern 10 with the second engaging portion 21 of the accessory wax pattern (the striking plate wax pattern 20), with a gap “a1”, “a2” being defined between the first engaging portion 12 and the second engaging portion 21. A contour of a golf club head is obtained after bonding of the second engaging portion 21 of the accessory wax pattern (the striking plate wax pattern 20). The back cavity 11 forms an undercut. At this time, an outer gap “a1” and an inner gap “a2” are respectively defined in a front side and a rear side of a joint area between the main body wax pattern 10 and the accessory wax pattern (the striking plate wax pattern 20).

Referring to FIGS. 4, 7, and 8, a third step of the method for manufacturing a golf club head in accordance with the present invention comprises filling a low-viscosity solvent 50 into the gaps “a1” and “a2”, combining the main body wax pattern 10 and the accessory wax pattern (the striking plate wax pattern 20) into a club head wax pattern. The low-viscosity solvent 50 is filled into the inner gap “a1” via the back cavity 11 of the main body wax pattern 10. Alternatively, the low-viscosity solvent 50 is directly filled into the outer gap “a2” via a front side of the main body wax pattern 10. The low-viscosity solvent 50 may be a volatile organic solvent with a viscosity smaller than 5 cps, such as aryl solvent, aliphatic solvent, or cyclane solvent. Preferably, the low-viscosity solvent 50 is selected from the group comprising toluene, xylene, acetone, petroleum leve, pentane, hexane, propyl bromide, and banana oil and combinations thereof.

As illustrated in FIG. 7, although the main body wax pattern and the accessory wax pattern (the striking plate wax pattern 20) have been engaged with each other, the low-viscosity solvent 50 permeates easily into the inner gap “a1” or the outer gap “a2”. After a period of time, as illustrated in FIG. 8, the low-viscosity solvent 50 slightly dissolves a wall delimiting the inner gap “a1” or a wall delimiting the outer gap “a2”. Mixing of the low-viscosity solvent 50 and the wax material increases the viscosity of the solvent 50. At room temperature of 25° C., the viscosity of the solvent 50 can be increased up to greater than 100 cps. Further, a capillary action is created between the gaps “a1” and “a2”, causing the wax to fill the gaps “a1” and “a2”. Further, the low-viscosity solvent 50 is volatile such that a bonding structure 51 for filling the inner gap “a1” or the outer gap “a2” can be formed by means of using the wax material of the main body wax pattern 10 and the wax material of the accessory wax pattern (the striking plate wax pattern 20). A golf club wax pattern 100 is thus obtained while assuring surface evenness in the joint area. Further, the outer gap “a1” and the inner gap “a2” between the main body wax pattern 10 and the accessory wax pattern (the striking plate wax pattern 20) may be as large as 0.3 mm without adversely affecting the resultant club head wax pattern 100 due to filling the gaps “a1” and “a2” with a low-viscosity solvent 50. The precision requirements of the club head wax pattern 100 can be lowered.

Further, while filling the low-viscosity solvent 50, the low-viscosity solvent 50 volatizes when comes in contact with the air without dissolving the wax material on the surfaces of the wax patterns 10 and 20 and without causing flaws in the surfaces of the wax patterns 10 and 20, although the low-viscosity solvent 50 may inadvertently soil the surfaces of the wax patterns 10 and 20.

Referring to FIGS. 4 and 9, a fourth step of the method for manufacturing a golf club head in accordance with the present invention comprises impregnating the club head wax pattern 100 in slurry to form a ceramic shell 30, and the club head wax pattern 100 is then released by heating, obtaining a ceramic shell 30, as shown in FIG. 10. The club head wax pattern 100 can be impregnated in zirconium slurry and stucco to form the ceramic shell 30, as known in the art. The ceramic shell 30 has a mold cavity 31 and a port (not shown). The hardened ceramic shell 30 is heated to melt the club head wax pattern 100, and the molten wax is then released out of the ceramic shell 30 to obtain a mold cavity 31. Since the low-viscosity solvent 50 has been volatized into the atmosphere, no bonding agent remains in the mold cavity 31. In other words, the wax releasing procedure can be carried out without difficulty.

Referring to FIG. 4, a fifth step of the method for manufacturing a golf club head in accordance with the present invention comprises carrying out a casting procedure with the ceramic shell 30 to produce a club head casting 40. More specifically, after releasing of the wax to form the mold cavity 31, molten metal is poured into the mold cavity 31 via the port of the ceramic shell 30. After cooling and hardening of the molten metal, a club head casting 40 is produced, and the club head casting 40 can be accessed after breaking the ceramic shell 30. As illustrated in FIG. 11, the club head casting 40 includes a back cavity 41, a main body 42, and a striking plate 43. The back cavity 41 may include an undercut according to need. No gap is generated in a joint area between a rear side of the striking plate 43 and the back cavity 41, reducing the surface grinding work in the back cavity 41. The walls delimiting the back cavity 41 can be coated and covered by balding finish, providing an aesthetically pleasing appearance for the walls delimiting the back cavity 41. Further, even if irregular protrusions are formed on joint areas of the front side of the club head casting 40, these irregular protrusions can be removed by surface grinding from outside without significantly increasing the processing difficulty.

FIG. 12 is an exploded perspective view of a modified embodiment of a club head wax pattern obtained from a first step of the method in accordance with the present invention. FIG. 13 is a perspective view of a golf club head manufactured from the club head wax pattern in FIG. 12. In this embodiment, the accessory wax pattern is a wax pattern for sealing 60, and bonding between the main body wax pattern 10 and the accessory wax pattern is substantially the same as that in the first embodiment. A through-hole 13 is defined in a bottom wall delimiting the back cavity 11, with a portion of a perimeter wall delimiting the through-hole 13 forming a first engaging portion 14. A perimeter of the wax pattern for sealing 60 forms a second engaging portion 61. As illustrated in FIG. 12, the second engaging portion 61 of the wax pattern for sealing 60 can be engaged with the first engaging portion 14 of the through-hole 13 of the main body wax pattern 60, with a gap being defined between the wax pattern for sealing 60 and the main body wax pattern 10. A low-viscosity solvent 50 is filled into the gap to provide a bonding structure, which is similar to the first embodiment. Thus, the gap between the wax pattern for sealing 60 and the main body wax pattern 10 can be reliably filled, obtaining improved surface evenness in the joint area. The wax pattern for sealing 60 seals an upper end or a lower end of the through-hole 13. In a case that the wax pattern for sealing 60 seals the lower end of the through-hole 13, the obtained club head casting 40 after release of wax and casting procedure includes a compartment 44 with an upwardly facing opening, as shown in FIG. 13. On the other hand, if the wax pattern for sealing 60 seals the upper end of the through-hole 13, the obtained club head casting 40 includes a compartment with a downwardly facing opening. In either case, the compartment may receive an alien object, such as a weight member with a relatively high specific gravity or a vibration-absorbing block with a high vibration-absorbing capacity.

As apparent from the foregoing, a method for manufacturing a golf club head in accordance with the present invention may effectively seal the inner gap “a2” by means of using a low-viscosity solvent 50, obtaining a flush bonding surface and thus improving surface evenness of the club head casting. Further, surface finishing of the surface of the club head casting is reduced, the precision requirements for the wax patterns is lowered, and the bonding procedure for the wax patterns is simplified. Further, golf club heads can be manufactured at an increased qualified product ratio.

While the principles of this invention have been disclosed in connection with specific embodiments, it should be understood by those skilled in the art that these descriptions are not intended to limit the scope of the invention, and that any modification and variation without departing the spirit of the invention is intended to be covered by the scope of this invention defined only by the appended claims. 

1. A method for manufacturing a golf club head, comprising: producing a main body wax pattern having a first engaging portion and an accessory wax pattern having a second engaging portion; engaging the first engaging portion of the main body wax pattern with the second engaging portion of the accessory wax pattern, with a gap being defined between the first engaging portion and the second engaging portion; filling a low-viscosity volatile solvent into the gap for forming a club head wax pattern by means of bonding of dissolved wax materials of the main body wax pattern and the accessory wax pattern; and impregnating the club head wax pattern in slurry to form a ceramic shell and then heating the ceramic shell to release wax in the ceramic shell; and proceeding with a casting procedure to form a club head casting in the ceramic shell.
 2. The method for manufacturing a golf club head as claimed in claim 1, wherein the low-viscosity volatile solvent is a volatile organic solvent having a viscosity smaller than 5 cps.
 3. The method for manufacturing a golf club head as claimed in claim 2, wherein the low-viscosity volatile solvent is selected from the group comprising aryl solvent, aliphatic solvent, and cyclane solvent.
 4. The method for manufacturing a golf club head as claimed in claim 2, wherein the low-viscosity volatile solvent is selected from the group comprising toluene, xylene, acetone, petroleum leve, pentane, hexane, propyl bromide, and banana oil and combinations thereof.
 5. The method for manufacturing a golf club head as claimed in claim 1, wherein the accessory wax pattern is a striking plate wax pattern.
 6. The method for manufacturing a golf club head as claimed in claim 5, wherein the main body wax pattern includes a back cavity extending from a front side of the main body wax pattern through a rear side of the main body wax pattern.
 7. The method for manufacturing a golf club head as claimed in claim 6, wherein the back cavity has an undercut.
 8. The method for manufacturing a golf club head as claimed in claim 6, wherein the back cavity includes a front side that forms the first engaging portion, the striking plate wax pattern including a rear side having a perimeter edge that forms the second engaging portion.
 9. The method for manufacturing a golf club head as claimed in claim 1, wherein the accessory wax pattern is a wax pattern for sealing.
 10. The method for manufacturing a golf club head as claimed in claim 9, wherein a bottom wall delimiting the back cavity includes a through-hole, a portion of a perimeter wall delimiting the through-hole forming the first engaging portion, the wax pattern for sealing including a perimeter that forms the second engaging portion.
 11. The method for manufacturing a golf club head as claimed in claim 10, wherein the wax pattern for sealing seals a lower end of the through-hole, the club head casting including a compartment with an upwardly facing opening.
 12. The method for manufacturing a golf club head as claimed in claim 10, wherein the wax pattern for sealing seals an upper end of the through-hole, the club head casting including a compartment with a downwardly facing opening. 